Protractor ruler and vernier mechanism therefor



Dec. 16, 1958 o. KLABUNDE 2,864,169

PROTRACTOR RULER AND A VERNIER MECHANISM THEREFOR Filed Feb. 5, 1954 2 Sheets-Sheet 1 0. KLABUNDE Dec. 16, 1958 PROTRACTOR RULER AND A VERNIER MECHANISM THEREFOR Filed Feb. 5, 1954 2 Sheets-Sheet 2 United States Patent PRUTRACTUR RULER AND VERNIER MECHANlSM THEREFOR Otto Klabunde, Chicago, Iii.

Application February 5, 1954, Serial No. 4%,348

12 Claims. (Cl. 33-75) The present invention relates to drafting instruments and has for its main object the provision of a ruler capable of angular adjustment at predetermined degrees whereby lines may be drawn at a predetermined angle.

Another object of the present invention is the provision of a suitable pro-tractor evice capable of adjusting a ruler at a desired predetermined angle.

A still further object of the present invention is the provision of a suitable connecting means between the protractor device and the ruler permitting angular shifting of the ruler with relation to the protractor device in order to bring the ruler to any angle of a predetermined degree, and wherein said connecting means may be capable of locking the ruler to the protractor device when the former has been angularly shifted to a predetermined degree.

A still further object of the present invention is the provision in a drafting instrument of a pivotally supported ruler for an angular swinging movement along an are divided into a plurality of degree units with means for locking the ruler to a support when the ruler has been angularly swung to any predetermined degree unit, with means for shifting the ruler to the extent of a fractional degree unit operable independently of said locking means.

Another object of the present invention is the provision of a protractor device having an are divided into a plurality of stops, representing full degree units, along which are a ruler may be angularly swung and rigidly locked in its swung position at any predetermined degree unit, with a vernier device whereby the ruler may be shifted to the extent of a fractional degree unit from its original locked position thereby bringing about a finer predetermined degree adjustment, with means for rigidly supporting the ruler in its angularly swung position as ultimately determined by said Vernier device.

With the above general objects in view and others that will appear as the invention is better understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings and pointed out in the appended claims.

in the drawings forming apart of this application and in which like designating characters refer to corresponding parts throughout the several views;

Fig. l is a plan elevational view of the present device;

Fig. 2 is a longitudinal cross sectional view therethrough, taken on line 2-2 of Fig. 1;

Pig. 3 is an enlarged fragmentary bottom plan elevational view of the ruler, forming a part of the present invention;

Fig. 4 is a transverse cross sectional view taken on line 44 of Fig. 1', and

Fig. 5 is a fragmentary side elevational view taken along the plane indicated by line 55 of Fig. 1.

Referring in detail to the present drawings there is shown a drafting board 10, upon which horizontal ruler 11 is supported.

Downwardly depending from the ends of said ruler 11 are flanges 12 which engage the side edges of board 10 and prevent horizontal shifting of ruler 11 and constitute guides for said ruler 11 with relation to board 10 from rolling off the board, especially when the latter is towards or away from the draftsman.

Aflixed to said ruler 11 by means of a plurality of screws 13 which are passed from the bottom of ruler 11, is an oblong pencil ledge 14 which prevents pencils from rolling off the board, especially when the later is at an incline.

The parts hereinabove described are usually found in conventional drafting boards. The invention constituting the subject matter of this application is adapted for disengageable attachment with said pencil ledge 14, the latter permitting the same to shift horizontally with relation to board 10. Ruler 11 being slidable in a vertical direction upon board 10 permits the present device for vertical adjustment with relation to board 10.

The present device includes plate 15 which is stationary with relation to the remaining parts of the device, and will therefore be referred to as stationary plate 15. At the forward end said stationary plate 15 supports in a rigid relation a U-shaped clamping member 16 which is adapted to frictionally engage said pencil ledge 14 upon which the same is supported for a Shifting movement longitudinally thereof. Said stationary plate 15 projects from said clamping member 16 at a point intermediate of its ends, whereby said stationary plate 15 may be rigidly supported in a spaced relation with board 10, as is clearly seen in Fig. 2.

The side edges of said stationary plate 15 are provided with downwardly depending flanges 17 acting as strengthening ribs for said plate 15. The right-hand flange 17, as viewed in Fig. 1, has an additional function which will be later described.

The outer end of said stationary plate 15 is arcuate as at 18, and centrally thereof is provided with a round opening for receiving therewithin a transparent sight piece 19, which centrally is provided with a vertical line marker 2%. Said marker 20 is in an axial relation with said plate 15 and in a perpendicular relation with the U-shaped clamp member 16.

The device further includes ruler 21 which is provided with bevelled edges 22. Said ruler 21 is by its front end disposed below said stationary plate 15, and has its lower face on the same plane as the lower face of ruler 11 so that when the instrument is upon the paper supported by board) the lower faces of both rulers are in contact therewith. V

Disposed below said stationary plate 15 is washer 23. Positioned below said washer 23 is toothed wheel 24. Optionally said washer 23 and wheel 24 maybe integrally formed. Superimposed upon ruler 21 is Vernier supporting plate 25. 'Wheel 24 and plate 25 are in a spaced relation and are maintained in that relation through the medium of a pair of spacers 26 which are in a coaxial relation with said ruler 21 and plate 25. Screws 27 passed through said plate 25, spacers 26 and wheel 24 rigidly engage and interconnect the said three parts.

Passed through ruler 21, plate 25, wheel 24, and washer 23 is cylindrical stud 23, thelower end of which is provided with a circumferential flange 29. The lower end of said stud 28 with flange 29 is flush with the lower face of said ruler 21, said flange being countersunk in said ruler 21, as is seen in Fig. 2.

The upper end of said stud 28 is engaged by screw 30 which is passed through said stationary plate 15. Washer 31 is interposed between said plate 15 and the head of said screw 30.

The front end of 'said ruler 21 is provided with a pair of arcuate transverse slots 32 which are in a coaxial relati n with said ruler 21. Said slots 32 are upon a. circle whose radius is equal to the distance between the axis of stud 28 and the axis of one of said screws 27. The ur ose of s id sl s 32 will be later described.

For the present it will suffice to say that ruler 21 and Vernier s pporting plate 25 are interconnected, in addition to stud 28. by leaf spring 33 at a distance from said stud 28 toward the rear ends of said ruler 21 and plate 25. By virtue of the interconnection between ruler 21 and plate 25 the two are capable of an ular shiftin movement in unison around said stud 28 which acts as a pivot. Of c urse. when said ruler 21 with plate 25 are angularly shifted around the said pivot, wheel 24 rotatably shifts around said stud 28. bearin in mind the ri id interconnection between said plate 25 and wheel 24 through the .medium of said screws 27 and s acers 26.

Made unon the rim of wheel 24 are 72 teeth 34 uniformly s aced so that the base of each to th will equal five de rees of a circle. The apices of a pair of adjacent teeth 34 also are spaced apart a distance equ l t five degrees f a circle traced through the apices of all of said teeth 34. K m At t o diame rica lv opposite p ints and on a hori-mntal line when said ruler 21 is a erpendicular relation, said line running throu h the depressions between the pairs of ad acent teeth 34. wheel 24 carries marks. Commencing with said 0 marks and continuing in an unward direction said wheel 24 along its arc is marked with n merals 1 to 9, inclusive. the successive numerals being distanced everv two teeth 34.

There is only one numeral 9 to indicate ninetv-degree position f ruler 21 when the l tter has been shifted to a perpendicu ar relation with said pencil ledge 14.

An ular shifting f ruler 21 in either direction from its vertical posi ion will cause said wheel 24 to be turned upon ivot 28; Fhiftin of said ruler 21 to an an ular position intermediately of the h rizontal and verti al. will bring one of said numerals within si ht 19. When f r instance numeral 6 has been brought within said sight 19 with marker 20 squarely in alinement with the de ression betw en a oair of adiacent teeth and indicated bv numeral 6. which is the position of ruler 21 indicated by dotted lines in Fig. 1, that will indicate that ruler 21 is at an incline 'at sixty de rees from horizontal. S id numerals, 0 to 9, being successively placed at a uniform distance equ l to a pair of said teeth 34. divide the qu rter of the circle into nine uniform divisions, each therefore representing ten degrees. It therefore follows that a point intermediatelv of a pair of adjacent numerals indicates a distance of five de rees fromeither ofthe adjacent numerals. Thus, when wheel 24 has been turned with marker 20 coming at rest at the depression between a pair of teeth 34 intermediately of 0 and 1, that will indicate that the acclivity of ruler 21 is at five degrees. Another example. when the ruler has been shifted in either direction with wheel 24 turned until marker 20 comes to rest at the depression between numerals 9 and 8, this will indicate that the ruler has been inclined from the horizontal to the extent of eighty-five degrees.

Note is made of the fact that when marker 20 rests at numeral 9 on wheel 24, then necessarily two 0 marks will be on a horizontal line in parallelism with pencil ledge 14.

When ruler 21 has been shifted to the right as viewed in Fig. l, and in parallelism with ruler 11 and pencil ledge 14, numeral 9 on wheel 24 will assume the position of the right-hand 0 mark as seen in Fig. 1, and the left-hand 0 mark, as seen in Fig. 1 will appear in register with marker 20. Similarly, when ruler 21 has been angularly shifted to the left as far as the same will go, and in parallelism with ruler 11 and pencil ledge 14, the 0 mark which appears at right will come in alinement with marker 20, while numeral 9 will assume the position of the left hand 0 mark as seen in Fig. 1. In both of these instances the 0 4 mark coming in alinement with marker 20 will indicate the horizontal position of ruler 21.

When either of the two 0 marks on wheel 24 comes in alinement with marker 20 ruler 21 will remain in parallelism with drafting ruler 11, on one or the other side of stationary supporting plate 15.

A suitable interlocking device between ruler 21 and stationary plate 15 is provided in order to maintain said ruler 21 in a stationary position and rigid with relation to said stationary plate 15 when said ruler has been angularly adjusted at a desired degree of acclivity. Without such interlocking ruler 21 would not be firm for guiding a writing instrument in order to trace a straight line at a predetermined degree from horizontal.

Said interlocking device includes resilient arm 35 which by one of its ends is affixed to the end of one of said flanges 1'7 by means of screw 36. The opposite free end of said arm 35 carried detent 37. Said arm 35 by its inherent nature tends by its free end to flex toward wheel 24 urging said detent 37 to fall within the interdental spaces defined by the adjacent pairs of teeth 34 upon said wheel 24, as is clearly seen in Fig. 1.

The active edge of said detent 37 is angular corresponding on a transverse cross section to the grooves defined by said teeth 34.

The length of said detent 37 is greater than the thickness of said resilient arm 35 in order that a portion of said detent 37 may remain oflset from the plane of said wheel 24 and may be in alinement with said washer 23, as is clearly seen in Fig. 5.

Said interlocking device further includes a V-shaped detent-deflecting member which embodies a pair of arms 38. At the apex of said member there is loop 39 formed which embraces the shank of screw 40. The opposite free ends of said arms 38 are bent towards each other and each defines loop 41. The arms 33 of said -shaped member are resilient and by their nature tend to flex towards each other in order that loops 41 may at all times flex in contact with the periphery of washer 23. The diameter of at least the proximate loop 41 to said detent 37 is greater than the distance between the nearest perimetral point and said detent 37 when the latter remains in engagement with said teeth 34 in order that said last named loop 41 may be capable of contacting said detent 37 and reflecting the same away from its engagement with the perimeter of wheel 24 for the purpose of shifting said detent 37 out of engagement with teeth 34. Portion of said detent 37 remaining in alinement with said washer 23 remains also in alinement with the adjacent arm 38 and loop 41 and therefore in the path of movement of the latter when said V-shaped member is shifted forwardly, that is toward the front end of stationary plate 15 and clamping member 16.

The front end of stationary plate 15 is provided with an oblong recess 42 in an axial relation therewith. Entering said recess 42 is a reduced boss 43 depending from knob 44. Screw 40 is driven through said boss 43 into the lower end of said knob 44 and by its head clamps loop 39 of the said V-shaped member to the lower end of said boss 43.

From the arrangement last hereinabove described it will be seen that the V-shaped member for actuating detent 37 is firmly bound to said knob 44. When said knob is shifted in the direction of said clamping member 16 the said V-shaped member will be simultaneously shifted therewith for the purpose of causing deflection of detent 37 from wheel 24 by virtue of the brushing thereagainst of the adjacent loop 4-1 as may be clearly visualized from the showing in Fig. 1.

" Whenever it is desired to shift ruler 21 for the purpose of setting the same at a desired degree of acclivity, first knob 44 is manually pressed in order to shift the latter toward clamping member 16. This will cause the deflection of detent 37 and out of its engagement with the rim of wheel 24 and teeth 34, as wasdescribed. With said detent out of engagement with teeth 34, and while maintaining knob 44 in its shifted position toward clamping member 16 ruler 21 is then angularly shifted in either direction with wheel 24 turning freely due to the disengagement therefrom of said detent37. When said ruler 21 has been brought to a desired position at a predetermined degree of its acclivity as indicated by marker 20 when the degree indicia upon the rim of wheel 24 at a desired point have come in alinement with said marker 26, knob 44 is then released and said knob 44 will automatically spring to its inoperative position thereby permitting detent 3'7, freed from its contact with the adjacent loop 41, to spring automatically into the space defined by a pair of adjacent teeth 34 oppositely of said detent 37. This action of detent 37 will cause a reasonably strong interengagement of Wheel 24 therewith for maintaining said ruler 21 at a reasonable degree of firmness permitting one or the opposite edge of said ruler to guide a pencil or any other writing instrument for drawing a line upon a medium below said ruler 21 at a predetermined degree of inclination from horizontal.

It is further observed that loops 41 are at a rather strong co-ntactual engagement with the rim of washer 23 due to the resiliency of arms 38 and tendency of said arms to fiex towards each other. Thus, when the manual hold at knob 44 is released said loops 41 alone will be sufficient to shift arms 33 and knob 44 to their inoperative position illustrated in Fig. 1, with the adjacent loop 41 out of contact with detent 37. This action is especially assured in view of the fact that the horizontal diametrical line through said loops 41 need never pass horizontal lines coextensive with the diameters of said washer 23 and wheel 24. That this does not occur recess 42 is made at a predetermined point in order that said loops 41 when shifted to the operative position with relation to detent 37 may never find themselves Within the semi-circles of said washer 23 and wheel 24 nearest to said clamping member 16.

From the hereinabove description it will be seen that the arc of wheel 24 has been divided into a plurality of stops forming upon the are a plurality of divisions each having an equal number of degrees, with means provided to lock the ruler at any selected stop in order to maintain the same in a firm position required of'a ruler in drafting operations. As has been seen each division corresponds to five degrees, permitting the ruler to be firmly locked to stationary plate 15 and wheel 24 at intervals which were multiples of five degrees. In the mechanism heretofore described there was no means for shifting the ruler to the extent of fractional angle within the five-degree angle. i-ience the provision of a suitable vernier device which will be presently described, which may permit the ruler to be shifted to a distance less than five degrees or even a fraction of one degree and which is capable of maintaining the ruler in a firm position bound to said stationary plate 15 and Wheel 24.

Made at the upper portion of ruler 21 is cavity 45. Merging with said cavity 45 is slot 46, the latter being in a substantially central and longitudinally coaxial relation with ruler 2.1. Said cavity 45 and slot 46 extend into the body of ruler 21 to a depth corresponding substantially to one-half of the thickness of the said ruler. Integrally formed with and downwardly depending from the lower face of said plate 25 is a pair of spaced oblong lugs i? which enter said cavity 45 and which are in a transverse relation with ruler 21 and plate 25. Positioned within the space defined by said lugs 47 and frictionally held therewithin is one end of said leaf spring 33. The portion of said leaf spring 33 adjacent said lugs 47 is curled in a semi-circle disposed toward the front end of ruler 21 and the remaining portion, thereof is directed lengthwise with relation to said ruler 21 and plate 25 into said slot 46, with the free end of said leaf spring 33 in engagement with the body portion of said ruler 21 resulting in a lateral wall 48 against which said spring 33 exerts pressure of a substantial degree. That pressure of said spring 33 tends to urge ruler 21 toward the righthand direction as viewed in Fig. 1.

Disk member 49 (Fig. 4) is inserted into a bore of a corresponding diameter from the bottom face of ruler 21 and adjacent the left edge of said ruler as viewed in Fig. 1. Integrally with said disk 49 and upwardly projecting therefrom is pin 50. Said pin 50 is in a concentric relation witA bore 51 which is of a diameter smaller than the diameter of said disk 49. Insertable over said pin 50 is boss 52 which is integrally formed with and downwardly projecting from circular stop member 53. Integrally formed with said stop member 53 and projecting in an upward direction therefrom is lug 54 of a reduced diamete Said lug 54 is in a concentric relation with said stop member 53 and boss 52.

The face of said lug 54 is provided with a line defining marker 55 which is in a transverse relation with ruler 21.

Originally said pin 50 may have a bulge intermediately of its ends and of a diameter greater than the diameter of the bore within said boss 52. By suitable tool which exerts pressure at the outer face of said disk 49 and the free end of said lug 54 said pin 50 may be forced into the bore of said boss 52 and said boss as a consequence thereof may be forced to expand against the body portion of ruler 21 adjacent said bore 51 completely filling same. In this manner disk 49 is firmly connected with stop member 53 by the expansion joint. These parts are rigidly engaged with ruler 21 by virtue of the expansion joint aforesaid in order to maintain the mark line 55 in its original position which is transverse with relation to said ruler 2.1.

it is noted that at the adjacent edge of plate 25 notch 56 is made wherein normally said stop member 53 enters, as is seen in Fig. l. The thickness of said stop member 53 corresponds to the thickness of plate 25 as is seen in Fig.4.

Rigidly afiixed to said plate 25 adjacent its rear end is a hollow knob 57 upwardly projecting from said plate 25. Set upon said knob 57 for free rotation therearound is sleeve 58, to the lower end of which helical cam 59 is rigidly afiixed. Said cam 59 is superimposed upon said plate 25 for a rotary movement thereupon when said sleeve 53 is manually turned. The width of said cam 59 corresponds to the height of said lug 54 as is clearly seen in Fig. 4. The upper end of said sleeve 58 terminates on the plane with the upper end of said knob 57. Screw 6b in threaded engagement with the upper end of said knob 57 partially overlaps by its head the upper end of said sleeve 58, thereby preventing the disengagement of said sleeve 58 from said knob 57 and maintaining cam 59 in contact with said plate 25. The upper peripheral portion of said sleeve 53 may be knurled for facilitating manual rotation of said sleeve 53 around said knob 57 and turning of said cam 59.

The edge of said helical cam 59 is fashioned along a spiral commencing at the it point and ending at point marked with numeral 5. At the 0 point the edge of said cam is nearest to the cams axis which coincides with the longitudinal axis of screw 60. From that point the edge spiral gradually recedes from the cams axis, so that at point 5 the cams edge is at a farthest distance from the cams axis.

When 0 point on the edge of cam 59 is in alinement with line marker 55, as seen in Fig. 1, spring 33, exerting a strong pressure at wall 48 tends to urge ruler 21 to the right direction as viewed in Fig. 1, urging stop member 53 within notch 56 and against the adjacent body portion of plate 25, simultaneously driving said lug 54 in contact with the edge of cam 59, as is seen in Fig. 4. Due to the action of said spring 33 said ruler 21 is .bound to said plate 25, with said stop member 53 and lug 54, particularly the latter, effectively barring further shifting movement of said ruler past said plate 25 to the right-hand direction as viewed in Fig. 1. By virtue of the action of said spring 33 of urging said stopmember 53 in contact with plate 25 and said lug 54 in contact with the rim of cam 59, said ruler 21 and plate 25 are effectively interconnected so that both are capable of angular shifting movement in unison around pivot 28 for the purpose of setting ruler 21 at a desired degree of acclivity as was hereinabove described. As was already noted ruler 21 is capable to be bound to wheel 24 at five-degree intervals.

Referring again to said cam 59 the rim thereof is divided into five divisions, numbered from 1 to 5 and commencing with the mark. When cam 59 is turned by manually rotating sleeve 58 in the clockwise direction, as viewed in Fig. 1, the receding edge of said cam will ride upon said lug 54, against the tension of spring 33, thereby deflecting stop member 53 against the body portion of plate 25 within notch 56, whereat the two were in contact when the 0 line of the cam was in alinement with marker 55.

Cam 59 is cut in such a manner as to correlate the degree of the recession of the operative edge of the cam away from its axis with the de ree of shifting of lug 54 away from the carns axis, and thereby of ruler 21. The recession of the cam resulting from its edge spiral is such that when on rotating of the cam, ruler 21 has been shifted with relation to plate 25 to the extent of one degree the point at which the edge of cam with relation to the marker 55 has come to a rest is marked with numeral 1 to indicate that the shifting of the cam to that point has shifted lug 54 away from plate 25 to the extent of one degree and consequently the ruler 21 to the same extent. Continuing further along the periphery of cam 59 when point 2 on its edge reaches marker 55 when said cam is shifted that will indicate that cam 59 has deflected ruler 21 to the extent of 2 degrees, at point 3 three degrees, at point 4 four degrees and at point 5 five degrees. The full range of the degrees to which cam 59 is capable of shifting ruler 21 with relation to plate 25 embraces five degrees, the disstance which is equivalent to one of the divisions upon the rim of wheel 24.

Intermediately of full degree numbers cam 59 is provided on its edge with intermediate line marks dividing each full degree range into six divisions each representing ten minutes, as seen in Fig. 1. So for example when earn 55 has been turned upon its axis with the first intermediate line mark past number 2 coming to rest opposite mark line 55 on lug 54 that position will indicate that ruler 21 has angularly shifted to the extent of two degrees and ten minutes with relation to plate 25.

-It is to be noted that angular shifting of ruler 21 with relation to plate 25, and consequently with relation to wheel 24 by the aid of the said vernier device including cam 59, does not in any manner affect said plate 25 or wheel 24. The latter two continue to remain in their adjusted position as determined by marker 20 in sight Pivot 23 acts as a fulcrum around which ruler 21 turns during the angular shifting movement of the latter with relation to plate 25. During the angular shifting movement of said ruler 21 the heads of screws 27 are not interfered with in any manner due to the fact that said heads are within said slots 32. Therefore, even at the maximum of shifting movement of ruler 21 by the vernier device, that is to the extent of five degrees, said heads of screws 27 at no time come in contact with the body of said ruler 21.

Since the degree divisions upon wheel 24 measure the degree of acclivity of ruler 21 and not necessarily that of plate 25, the latter maybe set at.a bias relativ'e to ruler 21 when the mark line 55 is in alinement with the 0 mark on the rim of cam 59, as seen in Fig. 1. This inceptional position of plate withrelation to ruler 21 is important, because that position does not allow plate 25 to extend beyond the right-hand edge of ruler 21 even when the latter has been shifted to the maximum of five degrees by the aid of cam 59, thereby rendering the right-hand edge of ruler 21, as viewed in Fig. 1, unobstructed for the writing instrument when the same is placed along the right-hand edge of ruler 21 in order to draw a line therealong.

The radial shoulder line 61 of cam 59 resulting from the spirality of the said cam is ahead of 0 mark on the rim of the cam and and defines a stop against which lug 54 bears when the cam is returned to its inoperative position when the 0 mark thereon comes in alinement with mark on said lug 54. Thus, on returning the cam to that inoperative position the very striking of shoulder 61 against lug 54 will indicate to the operator that he has returned the cam to the inoperative position without requiring the operator to give any particular notice to the alinement of the 0 line on cam 59, because the very striking of said shoulder against lug 54 must necessarily bring about that result.

Rearwardly of said shoulder 61 and past the S-degree mark the cam is provided with a radial extension 62 which constitutes a stop which bears against lug 54 when cam 59 has been turned to the S-degree mark upon the rim of the cam. In that latter position the S-degree mark will come in alinement with mark 55 upon lug 54 and simultaneously the latter will be hit by said extension 62. Said extension 62 also prevents the turning of the cam beyond the S-degree mark and further prevents lug 54 from springing back to the 0 mark from the cams rim adjacent the S-degree mark. This latter eventuality would result in an undue shock both to ruler 21 and cam 59.

From the hereinabove description it will be seen that when ruler 21 is angularly shifted to either direction from the vertical as seen in Fig. 1, to the extent of the full five-degree divisions indicated upon the rim of wheel 24 and determined by the line mark 20 in the sight 19, plate 25 with cam 59 will shift bodily with ruler 21 by virtue of the rigid connection of said plate 25 with wheel 24 through screws 27. Said wheel 24, plate 25 and ruler 21 will turn in unison upon pivot 28. It is noted that when ruler 21 is shifted from the vertical to' the right-hand direction as viewed in Fig. l, the five-degree marks on the left-hand quarter of wheel 24 Will come within sight 19. When however ruler 21 is shifted from the vertical to the left-hand direction as viewed in Fig. 1, the five-degree marks on the right-hand quarter will shift within sight 19. It is noted however that the shifting movement of ruler 21 with relation to plate 25 when actuated by the vernier device aforesaid is had to the counterclockwise direction, that is, from the right to the left as viewed in Fig. 1 and within the entire range of degrees indicated on wheel 24.

To measure therefor-e the acclivity of ruler 21 within the right-hand quarter of the circle described by wheel 24, that is the inclination of ruler 21 when the latter has been shifted in a clockwise direction from the vertical, which is the right-hand direction, as viewed in Fig. 1, including fractional degrees within the scale of five degrees by the aid of the Vernier device, the ruler is locked to wheel 24 at any given or desired five-degree division upon the rim of wheel 24. As a second step cam 59 is shifted to any desired point on its rim for the purpose of shifting ruler 21 to a fraction within the scale of S-degrees on the rim of said cam 55 and the latter fraction within the scale of S-degrees on cam 59 is added to the degree indication in sight 19. Thus for example when it is desired to shift the ruler to the extent of 34 degrees from the horizontal and on the right-hand side 'of the vertical, first ruler 21 is shifted until number 3 in tholeft-handquarter of the circle has come in alinement with marker 20 within sight 19. This will indicate that ruler 21 has been shifted from horizontal to 30 degrees of its inclination within the right hand quarter cam has shifted ruler 21, in this instance with relation "to plate 25, four additional degrees from the horizontal.

When four degrees of the shiftin of ruler 21 by the aid of the vernier device are added to the original thirty degrees of the rulers acclivity as determined by numeral 3 upon the rim of wheel 24 coming in alinement with marker 20, the sum will total 34 degrees indicating that ruler 21 rest at 34 degrees of its acclivity.

If it is desired to set ruler 21 at 34 degrees of the rulers inclination from the horizontal within the lefthand circle quarter, ruler 21 is shifted from the horizontal on the left hand side of the verticahas viewed in Fig. 1, until the notch intermediately of numbers 3 and-4 of the right-hand quarter circle upon wheel 24, as viewed in Fig. 1, has been alined with the mark line 20 in sight 19. This will indicate that ruler 21 has been shifted from the horizontal to the extent of 35 degrees. During this operation cam 5'? is of course maintained in its inoperative position with the mark line in alinement with line 55 on lug 54. As a second step cam 59 is then turned until l-degree mark has come in alinement with line 55 on said lug 54. This operation of the cam results in ruler 21 having been shifted with relation to plate 25 to the extent of one degree toward the horizontal on the left hand of the vertical, or one degree away from the vertical. When that one degree is subtracted from 35 degrees at which the ruler has been set as indicated by mark line 21) aforesaid, the resulting difference will amount to 34 degrees, the number of degrees at which ruler 21 is inclined away from the horizontal on the left hand side as viewed in Fig. 1.

As has already been indicated, preliminarily to the setting of ruler 21 at 30 and 35 degrees, respectively, in the above two examples, wheel 24 is first freed from the engagement by detent 37 by deflecting the latter from teeth 34- by forwardly shifting knob 44 for the purpose of shifting loop 41 for hearing against said detent 37. This will free wheel 24 from said detent 37 bringing about free angular shifting movement of ruler 21 and free rotary movement of wheel 24. Just assoon as the basic adjustment of ruler 21 has been made, with wheel 24 rotatably' shifted to indicate the rul-e-rs acclivity at 30 and 35 degrees, respectively, in the two examples given, by the aid of said line marker 20, detent 37 is again brought back to engage teeth 34. This latter result is very simply accomplished by merely releasing the manual hold at knob 44. This in turn will release pressure by the periphery'of washer 23 at the inner peripheral portions of loops 41, causing the latter to ride upon the periphery of said washer 23 in the direction away from the clamping member 16. This action of loops 41 is aided by the tendency of arms 38 and consequently 'of loops 41 by'the inherent tendency 'of'said arms 33 and loops '41 to flex towards each other. Thus, on release of knob 44 from the manual hold the action of the right-hand loop 11, as viewed in Fig. 1, to shift away from its engagement withdetent 3"] is automatic, Once loop 41 was released fromits engagement with detent 37 the latter springs back automatically withinthe notch between a pair of teeth 34- oppositely of said detent 37, due to the'inherent action of arm 35 to flex toward wheel 24.

p The lO minute divisions upon earn may be sub- "divided into smaller units. A mark line placed substantially centrally of a -minute division will divide the division into a pair of 5-minute divisions. 'Fo'rall practicalpurpo'ses however the divisions upon cam 59 into ijegree units corresponding'in'nuniberto the degrees in each' division upon wheel :24, astre'presented by'the degree measurement of the base of each tooth 34, and further subdividing each degree unit upon cam 59 into six 10-minute divisions, all as shown in Fig. 1, will suflice. Most accurate angle measurements at which ruler 21 is required to be set may be accomplished by the degree divisions upon wheel 24, and by the degree and 10-minute divisions upon cam 59 as is illustrated in Fig. 1. However, for the most precise and minute and hardly perceptible angle measurements, the subdividing of each 10-minute unit into ten minute divisions, and the latter into seconds, is not excluded. This can be done without departing from the principles of construction and operation of the present device.'

For the suggested minute angle measurements wheel 24 could be divided into 360 divisions each representing one degree, instead of 72 divisions, each representing five degrees, as shown in Fig. 1. For the suggested division of wheel 24 into 360-degree units the wheel should be much larger in diameter. Of course, when each tooth 34 corresponds to one degree, then obviously the rim of cam 59 need be subdivided into divisions within the range of a single degree, such as minutes and seconds. For best results perhaps the radius of cam 59 would be required to be longer, or cam 59 farther removed from wheel 24 than the distance now suggested by the drawings. Greater radius of cam 59 would perhaps requirethe greater width in ruler 21 in order that cam 59 may at no time overlap the edges of the ruler because such eventuality would interfere with the tracing of a line therealong by a writing instrument.

From the hereinabove description it will be apparent that there is hardly any area upon the drafting medium supported upon board in upon which a line at a predetermined degree of acclivity could not be drawn. In this respect the instrument is made quite versatile due to its being capable of adjustment to or away from the draftsman by virtue of the shiftability in that direction of horizontal ruler 11 while guided by flanges 12 in engagement with the side edges of board 14? and due to the shiftability of the device laterally in either direction by virtue of the adjustability in that direction of the clamping member 16 upon pencil ledge 14.

Note is being made of an important feature of the present device, namely, that the same is capable of measuring the degree of declivity, that is the degree of inclination of ruler 21 in a downward direction from the horizontal line, that is in a downward direction from the horizontal ruler 11. All that is required to convert and condition the device to measure the declivity of ruler 21 is in inversion of the device, that is placing of the device in an inverted position from that shown in Fig. 1, and of course con necting clamping member 16 with pencil ledge 14 while the device remains in an inverted position with the free end of ruler 21 disposed towards the operator. Therefore, notwithstanding the fact that the instant specification refers only to the acclivity of the ruler, it is to be understood that the term acclivity shall include also the capacity of the instrument to measure and determine the degree of declivity of a line or of the ruler, particularly in view of the fact that the inversion of the instrument requires no changes or modifications of the mechanism.

The instrument herein disclosed may be used for general drafting purposes wherever thedrawing of lines at a required degree of inclination, up or down from horizontal, may be needed, including trigonometric functions, survey plats, analytic geometry and a variety of other purposes. Another important use of the instrument includes the duplication of lines made at particular degrees of inclination. The degree of inclination of a line may be easily found and a duplication or transfer thereof at the determined inclination to a paper sheet may be made with the greatest facility and accuracy by the aid of the present claimed.

metric horizontal line with relation to wheel 24 so that no matter to what extent said wheel 24 has been turned in either direction upon pivot 28 said detent will at all times fall within the notch defined by a pair of adjacent teeth 34, provided that marker 2% is in alinement with the center of a notch defined by any pair of adjacent teeth 34.

From what has been said it is clear that detent 37 and teeth upon wheel 24 act as a pawl and ratchet device for the purpose of locking ruler 21 in its angular adjusted position at any predetermined degree as indicated by marker coming in register with the indicia upon the degree scale in wheel 24. Said degree scale conforms to the several identical divisions determined by said teeth 34.

As is obvious a manual pressure imparted to ruler 21 in order to angularly shift the same is capable of overcoming the pressure of detent 37 upon teeth 34 and causing said detent 37 to ride upon said teeth 34 in a clicking fashion. Although such operation is not excluded under all conditions and would eliminate'the necessity of the employment of the detent deflecting device including arms 33, loop 41 and knob 44, such operation however would in time result in the wear of teeth 34 and detent'37. For this reason it is preferable to use the said deflecting device in order to shift detent 37 away from teeth 34 while ruler 21 is being angularly swung in order to set the same at a predetermined degree as indicated by said marker 26 upon the degree scale. Furthermore, ruler 21 is capable of angular shifting with greater facility and case before bringing it to the ultimately required set position if the same is not impeded by the intermittent click vibrations resulting from the riding of detent 37 upon teeth 34. Hence the provision of the detent deflecting device aforesaid.

Considering the invention in its aspect independent from the Vernier device ruler 21 may be deemed as rigidly connected with wheel 24 through pivot 28, plate 25 and spring 33, because said ruler does swing in unison with the rotatable turning of wheel 24 to the extent of the full degree units represented by teeth 34 and the degree scale based thereon on the rim of said wheel 24.

Wheel 24 need notnecessarily be of an arcuate formation if teeth 34 are made to extend from a face of a plate of any configuration.

At its forward end plate 25 is provided with a pair of arcuate slots 63 in an equidistant relation with pivot 28, through which slots screws 27 are extended to engage wheel 24. On loosening said screws 27 plate 25 and ruler 21 may be bodil angularly shifted upon pivot 28. The body portions of plate 25 adjacent the ends of slots 63 coming in contact with the shanks of screws 27 limit the angular shifting movement of said plate 25 and said ruler 21 therewith. This shifting is wholly independently of wheel 24 and is done for the purpose of adjusting the relative position of ruler 21 with respect to wheel 24 and the degree unit indicia thereon. Upon proper adjustment of said'ruler 21 with respect to wheel 24 having been made screws 27 are tightened in order that the heads thereof may clamp plate 25 to spacers 26 and through them to said wheel 24. The adjustment through said screws 27 and slots 63 may be necessary in order to condition ruler 21 for a perfect horizontality when the same has been shifted to either one of the 0 marks upon the degree indicia' as indicated by marker 20. This adjustment may be especially required in the event drafting ruler 11 or pencil ledge 14 or either of them are not in a true horizontal position. Notwithstanding the latter eventuality ruler 21 when swung to horizontal will assume a true horizontal position irrespective whether the latter is in parallelism with the drafting ruler 11 or not.

While there are described herein preferred embodiments of thepresent invention, it is nevertheless to be understood that minor changes may be made therein without departing from the spirit and scope of the invention as 12 What I claim as new is: 1. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler mounted upon said pivot for angular shifting movement therearound and having two substantially parallel ruling edges, 21 plate mounted upon said pivot in superposed relation to said ruler, said plate being narrower than said ruler and having'its edges disposed inwardly of the rulingedges on said ruler, a resilient connecting means between said ruler and said plate, during the angular shifting movement of said ruler said plate being adapted for bodily movement therewith, means for measuring the degree units to which said ruler has been angularly shifted, means for angularly shifting said ruler with respect to said plate to an extent of a fractional degree unit against the action of said resilient connecting means, and means for measuring the fractional degree unit to which said ruler has shifted by the operation of said last named means.

2. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler mounted upon said pivot and having two substantially parallel ruling edges, a plate mounted upon said pivot in superposed relation to said ruler, said plate being narrower than said ruler and having its edges disposed inwardly of the ruling edges on said ruler, a resilient tensioning connecting means between said ruler and said plate urging said ruler toward a position in which one of its ruling edges is closer to said plate than the other of its ruling edges, said resilient tensioning connecting means permitting an angular shifting movement of said ruler and said plate in unison around said pivot to an extent of full degree units, means for measuring the degree units to which said ruler has been angularly shifted, means for angularly shifting said ruler with respect to said plate to an extent of a fractional degree unit, said last named means being operable against the action of said resilient tensioning connecting means, and means for measuring the fractional degree unit to which said ruler has been angularly shifted with respect to said plate by the operation of said last named means.

3. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler mounted upon said pivot, a plate mounted upon said pivot, a resilient tensioning connecting means between said ruler and said plate, said resilient tensioning connecting means permitting an angular shifting movement of said ruler and said plate in unison around said pivot to an extent of full degree units, means for measuring the degree units to which said ruler has been angularly shifted, a cam follower on said ruler, a cam rotatably mounted on said plate, on operation of said cam the latter being adapted to bear against said cam follower for angular shifting thereof to an extent of a fractional degree unit, said last named angular shifting being against the action of said resilient tensioning connecting means, and means carried by said cam and said ruler for measuring the fractional degree unit to which said ruler has been angularly shifted with respect to said plate by the operation of said cam.

4. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler mounted upon said pivot, a plate mounted upon said pivot, a resilient tensioning connecting means between said ruler and said plate, said resilient tensioning connecting means permitting an angular shifting movement of said ruler and said plate in unison around said pivot to an extent of full degree units, means for locking said plate to said stationary supporting member at a predetermined degree unit to which said ruler has been angularly shifted, a lug carried by said ruler, a cam rotatably mounted on said plate with the low point of the cam surface in vertical alignment with an edge of said plate, on operation of said cam the latter being adapted tobear against said lug for angular shifting of said ruler to an extent of a fractional degree unit against the action of said resilient tensioning connecting means, the surface of said cam including afirst generally radial stop portion for preventing rotation of said cam in one direction from the position in which'its low point and the edge of said plate bear against said lug and a second generally radial stop portion for preventing rotation of said cam in the opposite direction beyond the position corresponding to a shift of the ruler'relative to the plate amounting to a full degree unit, and means carried by said cam for determining the fractional degree unit to which said ruler has been angularly shifted with respect to said plate by the operation of said cam.

5. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a plate mounted upon said pivot, a ruler mounted upon said pivot for angular shifting movement therearound, an oblong plate in a superimposed relation with said ruler, said oblong plate being rigidly connected with said plate, during the angular shifting movement of said ruler said plate and said oblong plate being adapted for angular shifting therewith, a scale of degree units carried by said plate, a marker carried by said stationary supporting member for indicating the degree units to which said ruler has been angularly shifted, means for locking said plate to said stationary supporting member when the former has been angularly shifted to a predetermined degree unit indicated by said marker and said scale, and a Vernier device supported upon said oblong plate for shifting said ruler to the extent of a fractional degree unit, said latter shifting of said ruler being independent of the shifting of said plate and said oblong plate.

6. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler, a rotatable member, a plate in a superimposed relation with said ruler, said plate being rigidly connected with said rotatable member, said ruler and said rotatable member being mounted upon said pivot, a resilient connecting means between said ruler and said plate in a spaced relation with said pivot, said ruler being adapted for angular shifting movement upon said pivot, during the angular shifting movement of said ruler the latter being adapted to induce to said plate the simultaneous angular shifting movement therewith through said rotatable member and said resilient connecting means, means carried by said rotatable memher and said stationary supporting member for indicating the degree units to which said ruler has been angularly shifted, releasable means for locking said rotatable member to said stationary supporting member at a predetermined degree unit to which said ruler has been shifted for rendering said plate rigid with respect to said stationary supporting member, a lug carried by said ruler, a cam carried by said plate in a spaced relation with said pivot, said cam normally bearing against said lug, on operation of said cam the latter being adapted to deflect said lug for shifting said ruler with relation to said plate to the extent of a fractional degree unit, and means upon said cam and said lug for indicating the fractional unit to which said ruler has been shifted with relation to said plate on operation of said cam.

7. A drafting instrument comprising a stationary supporting member, a pivot depending from said stationary supporting member, a ruler, a rotatable member, a plate in a superimposed relation with said ruler, said plate being rigidly connected with said rotatable member, said ruler and said rotatable member being mounted upon said pivot, said ruler being provided with a cavity extending through the face of said ruler adjacent said plate, a spring affixed by one of its ends to said plate, the other end of said spring entering said cavity for bearing against the body portion of said ruler adjacent said cavity, said cavity and said spring being in a spaced relation with said pivot, said ruler being adapted for angular shifting movement upon said pivot, meanscarried by said rotatable member and saidstationary supporting member for indicating the full degree units to which said ruler has been angularly shifted, releasable means for locking said rotatable member to said stationary supporting member when said ruler has been angularly shifted to a predetermined degree unit for maintaining said plate rigid with respect to said stationary supporting member, a lug carried by said ruler, a cam carried by said plate in a spaced relation with said pivot, said spring bearing against the body portion of said ruler adjacent said cavity for urging said lug in a tensioned contact with said cam, on operation of said cam the latter being adapted to deflect said lug and said ruler against the action of said spring for angularly shifting said ruler upon said pivot with relation to said plate to the extent of a fractional degree unit, and means uponsaid cam and said lug for indicating the fractional degree unit to which said ruler has been shifted with relation to said plate by'the operation of said cam, said ruler during its angular shifting movement to the full degree units being capable of inducing bodily shifting movement therewith of said rotatable member and of said plate due to the interconnection by said pivot and said spring.

8. A drafting instrument attachable to a drafting ruler including a strip disposed thereabove in a longitudinal relation, comprising a clamping member, said clamping member being adapted for disengageable positioning upon said strip in a longitudinal sliding relation therewith, a stationary supporting member carried by said clamping member in a substantially transverse relation therewith, a pivot depending from said stationary supporting member, a ruler mounted upon said'pivot for an angular swinging movement thereon along a ISO-degree are having its points of inception upon a line substantially in parallelism with said drafting ruler, a plate mounted upon said pivot, a resilient tensioning connecting means between said ruler and said plate, said resilient tensioning connecting means permitting an angular shifting movement of said ruler and said plate in unison around said pivot to an extent of full degree units, means for indicating full degree units of the swinging movement of said ruler away from said line on both sides of said stationary supporting member, means for locking said plate to said stationary supporting member at a predetermined full degree unit, a cam follower on said ruler, a cam rotatably mounted on said plate so as to bear against said cam follower to shift it angularly to an extent of a fractional degree unit against the action of said resilient tensioning connecting means, said cam being operable without affecting the locked engagement of said plate to said stationary supporting member.

9. A drafting instrument comprising a stationary member, a rotatable member, a pivot depending from said stationary member and having an annular bearing surface, said pivot being extended through said rotatable member, a ruler afiixed to said rotatable member, said ruler being adapted for adjustable angular swinging movement with relation to said stationary member, during the angular swinging movement of said ruler said rotatable member being adapted for turning upon said pivot, a plurality of teeth arranged in an are upon said rotatable member arranged in an equidistant relation with said pivot, a detent resiliently supported by said stationary member for normally tending to spring into engagement with said teeth for maintaining said ruler locked with relation to said stationary member, a knob mounted for limited shifting movement on said stationary member toward and away from said pivot, and a spring including a central looped portion connected to said knob and a pair of spaced end portions tending to spring together and bearing against the side of said annular bearing surface disposed away from said knob as said knob is shifted between its limiting positions, whereby said knob is automatically biased toward said pivot and whereby movement of said knob away from said pivot causessaid end portions of said spring to move away from each other, said detent including a portion disposed in the path of movement of said spring so as to be shifted away from engagement with said teeth as said knob is moved away from said pivot.

10. A drafting instrument adapted to cooperate with a ruling device positioned upon the upper surface of a drafting board for movement in a direction parallel to an edge of the board, said instrument comprising a member adapted to be attached to said ruling device for movement therewith, a pivot depending from said member at a point spaced from said ruling device, a wheel connected to said pivot below said member for rotation relative I to said member and having an arcuate set of teeth thereon, a detent mounted upon said member for movement into and out of holding engagement with said teeth, a plate connected to said pivot below said member for rotation relative to said member, means for fixing said plate to said wheel but permitting angular adjustment of said plate relative to said wheel, and an elongated ruler connected to said plate and connected to said pivot below said plate for rotation relative to said member.

11. A drafting instrument attachable to a ruling device positioned upon the surface of a drafting board for movement in a direction parallel to an edge of the board and having a longitudinally extending projection upon its upper surface, said instrument comprising a clamp adapted to be removably positioned upon said projection for sliding movement along said projection, a support member carried by said clamp and extending horizontally beyond said ruling device, a pivot depending from said support member at a point spaced from said ruling device, a rotatable member mounted on said pivot below said support member and having an arcuate set of teeth thereon, a detent mounted upon said support member for movement into and out of holding engagement with said teeth and being biased toward a position in which it engages said teeth, said detent and said teeth being shaped to lock said rotatable member against rotation in either direction when said detent is in engagement with said teeth, a ruler connected to said rotatable member for angular movement therewith, a knob mounted upon said support member for shifting movement and having a portion projecting upwardly from said support member, an arm connected to said knob below said support member, said arm being normally spaced from said detent and being movable into contact with said detent upon shifting of said knob for deflecting said detent away from said teeth when it is desired to rotate said rotatable member to change the inclination of said ruler relative to said ruling device, and means for automatically returning said knob and said arm to their normal inoperative positions.

12. A drafting instrument adapted to cooperate with a ruling device positioned upon the upper surface of a drafting board for movement in a direction parallel to an edge of the board, said instrument comprising a member adapted to be attached to said ruling device for movement therewith, a pivot depending from said member at a point spaced from said ruling device, a wheel connected to said pivot below said member for rotation relative to said member and having a set of teeth extending entirely around its circumferential edge, a detent mounted upon said member for movement in a substantially horizontal plane into and out of holding engagement with said teeth and being biased toward a position in which it engages said teeth, means including a portion protruding upwardly from the said member for moving said detent away from said teeth when it is desired to rotate said wheel relative to said member, a plate connected to pivot below said member for rotation relative to said member and having a portion extending horizontally beyond an edge of said member, means for fixing said plate to said wheel but permitting angular adjustment of said plate relative to said wheel, a cam mounted for rotation about a vertical axis on said portion of said plate in a position such that a portion of said cam may protrude beyond an edge of said plate, an elongated ruler connected to said pivot below said plate for rotation relative to said member, stop means fixed to said ruler and extending upwardly in position to bear against said portion of said cam, and spring means connected to said ruler and said plate for urging said ruler into contact with said cam.

References Cited in the file of thispatent UNITED STATES PATENTS 397,128 Hester Feb. 5, 1889 513,183 Hatch et al. Ian. 23, 1894 700,304 Coombs May 20, 1902 814,690 Green Mar. 13, 1906 1,180,083 Shiley Apr. 18, 1916 1,230,901 Houghton June 26, 1917 1,329,005 Neumaier Jan. 27, 1920 1,959,832 Lesh May 22, 1934 2,124,358 Vancura July 19, 1938 2,243,731 Eubanks May 27, 1941 2,594,574 Marsden Apr. 29, 1952 2,735,185 Naphtal Feb. 21, 1956 FOREIGN PATENTS 967,145 France Mar. 22, 1950 135,651 Great Britain Dec. 4, 1919 164,866 Switzerland Jan. 2, 1934 

